Based on the principle of result oriented，Public view and Policy oriented，the index system of assessing online openness of government affairs was constructed. The quantitative evaluation on the online openness of government affairs from 106 county governments was made according to the index system. Results show that in 2017，the average score of online openness of government affairs from 106 county governments in Henan Province was 63.3 points which breakthrough pass line for the first time，top five scores are Zhecheng，Gongyi，Qinyang，Wugang，Xuchang and Neixiang. The same index system was used to 18 Municipal Governments of Henan，the results showed that in 2017，the average score of the online openness of government affairs in Henan's 18 Municipal Governments was 80.2 points，which was higher than that of the county government 17 points，the top five scores of Zhengzhou，Xuchang，Nanyang，Zhumadian，Kaifeng and Luoyang. The study also found that the disclosure level of county-level government online information is mainly affected by the lead of municipal governments and per capita public revenue，while the municipal government's online openness of government affairs are not affected by these factors.